The present invention relates generally to fuel systems for vehicles and, more particularly, to a fuel sensor system for a fuel system of a vehicle.
It is known to provide a fuel system for a vehicle, which includes a fuel tank, a fuel delivery module, a fuel filter, a fuel pressure regulator, a fuel rail, and fuel injectors. In the fuel system, a fuel pump of the fuel delivery module typically runs at a maximum flow at all times to deliver fuel to an engine of the vehicle. When the engine is turned off, heat from the engine continues to heat the fuel rail and causes the pressure in the fuel rail to rise. The increased pressure causes the fuel pressure regulator to open and relieve the pressure by dumping the heated fuel into the fuel tank, which generates vapor in the fuel tank.
As emission regulations for vehicles become tighter, new ways to decrease emissions are desired. For exhaust hydrocarbon (HC) emissions, the air-to-fuel ratio during cold start is a critical variable. If the air-fuel mixture is too rich, extra exhaust HC is emitted. If the air-fuel mixture is too lean, the engine has poor performance. It is known that gasoline type fuel varies in volatility. One approach to improve control of the air-to-fuel ratio during cold start is to measure the drivability index (DI) of the fuel at the end of each trip, just after the engine is turned off. The measured value is stored and used in a fueling algorithm for the cold start at the beginning of the next trip.
To measure the DI, a small sample of fuel is heated in the fuel tank, and its evaporation is monitored as a function of temperature or time. An interdigitated sensor can be used to monitor the evaporation. An example of such interdigitated sensor is described in pending U.S. patent application Ser. No. 09/924,873 filed Aug. 8, 2001.However, the interdigitated sensor needs to be contacted by the fuel before the measurement can be made.
It is desirable to contact a fuel volatility sensor with fuel before a measurement of drivability index of the fuel is made. It is also desirable to provide fuel to a fuel volatility sensor in a fuel system of a vehicle. It is further desirable to obtain a fuel sample for a fuel volatility sensor in a fuel system of a vehicle. Therefore, there is a need in the art to provide a fuel sensor system for a fuel system that meets these desires.
It is, therefore, one object of the present invention to provide a fuel sensor system for a fuel system of a vehicle.
It is another object of the present invention to provide a system that obtains a fuel sample for a fuel volatility sensor to measure a property of the fuel such as a drivability index of the fuel.
To achieve the foregoing objects, the present invention is a fuel sensor system for a vehicle including a fuel pump adapted to be disposed in a fuel tank to pump fuel from the fuel tank to an engine of the vehicle. The fuel sensor system also includes a fuel sensor adapted to be disposed in the fuel tank to sense a property of the fuel. The fuel sensor system further includes a jet pump connected to the fuel pump to fill the fuel sensor with a fuel sample of the fuel.
One advantage of the present invention is that a fuel sensor system is provided for a vehicle. Another advantage of the present invention is that the fuel sensor system uses a jet pump to deluge a fuel volatility sensor to measure a property of the fuel such as the drivability index of the fuel. Yet another advantage of the present invention is that the fuel sensor system obtains a fuel sample for a fuel volatility sensor without adding any moving parts. Still another advantage of the present invention is that the fuel sensor system samples fuel for a fuel volatility sensor that is relatively less expensive and bulky without moving parts.
Other objects, features, and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.